Direct solenoid drive imprinting mechanism

ABSTRACT

An apparatus for embossing sheet material by applying pressure to punch and die members positioned on both sides of the sheet material using force developed by one or more solenoids to force the punch and die members together to apply an imprinting force. In order to reduce the impact force, noise and wear on the mechanical parts, the solenoid may be energized in two separate steps, the first to move the punch and die members into contact with the surface of the card and the second to apply the embossing force to the punch and die members. Both rotary and linear solenoids may be used with differing coupling linkages in various embodiments of the embossing mechanism.

This is a continuation, of application Ser. No. 07/830,993, filed onFeb. 5, 1992, entitled DIRECT SOLENOID DRIVE IMPRINTING MECHANISM, nowabandoned which is a continuation of application Ser. No. 07/607,853,filed Nov. 1, 1990, now abandoned, which is a continuation ofapplication Ser. No. 07/204,499, filed on Jun. 9, 1988, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an embossing system and moreparticularly to a solenoid driven embossing mechanism for embossinginformation onto a common credit card.

Automated embossing systems have found wide acceptance in the field. Twosuch systems are disclosed in U.S. Pat. Nos. RE 27,809 to Drillick andU.S. Pat. No. 3,820,454 to Hencley et al and U. S. Pat. No. 3,820,455.

U.S. Pat. Nos. 4,271,012, 4,180,338 and 4,088,216 all show a systemutilizing a pair of embossing heads in a card transport mechanism forrapidly positioning a card to receive characters from punch and diemembers carried by punch and die wheels. The characters are applied tovarious embossing locations on the surface of a card. The application ofthe embossing forces to the punch and die members is, in all of thesystems shown in the patents listed above, by a motorized cam driven,continuously oscillating bail arm mechanism for mechanically driving thepunch and die members. Such systems are mechanically complex and quiteheavy because of the necessity of providing extremely strong mechanicalstructures for mechanically developing and coupling the embossing forcesto the punch and die elements. Such prior art structures are notparticularly helpful for use in simple and common lower volumeapplications where machines having reduced physical size and weight andlower cost are particularly necessary.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide apparatus forembossing sheet material which provides the embossing function withoutthe use of motor driven cams and continuously oscillating bail arms todrive the punch and die elements. The apparatus is of reduced size andweight relative to what has been previously available.

Another object of the invention is to provide apparatus for embossingsheet material and which includes a plurality of cooperating punches anddies inserted in slots positioned about circumference of punch and diewheels rotatable in synchronism with each other to permit positioning ofa selected punch and die pair on both sides of sheet material positionedin an emboss location and improved embossing pressure applyingmechanism. The mechanism includes at least one solenoid mechanismmounted on the frame and constructed and arranged for effecting linearmovement of punch and die members along an embossing axis when thesolenoid is energized from a first position to a second position byapplication of a suitable voltage; linkage means coupled to the shaft ofeach of the solenoid means and including drive pin means for impartingmotion, along the embossing axis, of the solenoid shaft to an embossingelement, the linkage means also including spring restraining means forretaining the solenoid shaft in the first unactuated condition; anddriver means for applying voltage for energizing the solenoid means toapply a selected character to sheet material positioned in the embossingarea.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the important elements of the embossingmechanism shown in section taken vertically through the rotational axisof the printwheel with some elements not sectioned for illustrativepurposes.

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 1.

FIG. 4 is a schematic electrical diagram of the solenoid drivecircuitry.

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 1.

FIG. 6 is a fragmentary sectional view of an alternate embodiment of anembossing mechanism utilizing only a single solenoid and is the viewthat would be seen viewing along the line 6--6 of FIG. 5.

FIG. 7 is a sectional view of another embodiment of the embossingmechanism with the section taken in the same manner as FIG. 1.

FIG. 8 is a sectional view of yet another embodiment of the embossingmechanism with the section taken in the same manner as FIGS. 1 and 7.

FIG. 9 is a sectional view of a further embodiment of the embossingmechanism with the section taken vertically through the rotational axisof the printwheel.

FIG. 10 is a sectional view of a still further embodiment of theembossing mechanism with the section taken in the same manner as in FIG.9.

FIG. 11 is a sectional view of an additional embodiment of the embossingmechanism with the section taken in the same manner as in FIG. 9.

FIG. 12 is a sectional view of a further alternative embodiment of theembossing mechanism with the section taken in the same manner as in FIG.9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the several embodiments of the invention shown, parts common to theseveral embodiments may be identified by the same reference characters.

FIG. 1 shows the important elements of one of the preferred embodimentsof the direct solenoid drive embossing mechanism 10. The punch and dieembossing elements of the basic embossing system are similar to what isshown in U.S. Pat. No. 4,271,012 and U.S. Pat. No. 4,519,600, both ofwhich are assigned to the assignee of the prevent invention. In thoseand other prior art embossing mechanisms, a pair of type element wheels12 and 14 are mounted on a common shaft 16 and secured by set screws 18located in hubs 20. (Whenever reference numerals are used throughout thespecification, they refer to structures in the present invention.) Ofcourse, use of a single shaft 16 is not necessary since other means canbe utilized to synchronize the rotation of wheels 12 and 14, even ifthey are mounted on separate but coaxial shafts. Shaft 16 is supportedon frame 22 by bearings 24. Shaft 16 is driven by positioning mechanismsas shown in U.S. Pat. No. 4,271,012 so that appropriate pairs of punchelements, such as 26, on wheel 14 and die elements, such as 28, on wheel12 are positioned for embossing. FIG. 2 shows the embossing punch 26aligned with an aperture 25 in a stationary guide plate 27. Guide plates27 define an embossing area 30 between them.

A suitable card or sheet material 32 is positioned with the area to beimprinted located in the embossing area 30. The card handling mechanismshown in U.S. Pat. Nos. 4,271,012 or 4,519,600, for example, provides asuitable mechanism for positioning card 32 and moving it throughembossing area to receive a series of embossed characters from punch anddie members 26 and 28 and other selected punch and die members carriedby wheels 14 and 12.

In prior patents such as U.S. Pat. Nos. 4,271,012 and 4,591,600, theembossing pressure was applied to punch and die members 26 and 28 usinga complex mechanical mechanism driven by a pair of oscillatingcontinuously motor driven bail arms utilizing a complex mechanicallinkage to bring force from the movement of the continuously oscillatingbail arms to the punch and die members. In the preferred embodiment ofthe present invention, a variety of greatly simplified solenoid actuateddrive mechanisms have been devised to eliminate the use of the motor camand continuously driven oscillating bail arms and the complex mechanicallinkages, relying instead upon the considerable embossing forces whichcan be developed by an improved linear solenoid.

In the preferred embodiments shown in FIGS. 1 through 6, linearsolenoids 40 are each secured to frame 22 with their shafts 42projecting and aligned with the axis of linear movement of punch and diemembers 26 and 28 into and away from embossing area 30. Suitable linearsolenoids 40 are manufactured by Ledex Inc., 801 Scholz Drive, Vandalia,Ohio 45377, and described as axial solenoids Part Nos. 189987 or 187790.

In FIG. 1, shaft 42 is secured in an inner sleeve 44 which may beadhesively secured to shaft 42 using a set screw, by shrink fit or bythe use of a suitable adhesive. Alternatively, shaft 42 can be threadedto threadably engage inner threads on outer sleeve 50. Sleeve 44 has aset of outer threads 46 which engage corresponding threads 48 on theinner wall of outer sleeve 50. Outer sleeve 50 is secured to innersleeve 44 using a set screw 52 which can be tightened to apply pressureto the threads of inner sleeve 44. In order to protect the threads 46 ofinner sleeve 44, a plastic plug 53 is inserted in the hole in outersleeve 50 before set screw 52 is inserted, thereby providing a resilientlocking action which is not likely to damage outer threads 46 of innersleeve 44. Outer sleeve 50 has a hardened driver pin 56 mounted in frontof it which is slidably supported in a plain bearing 58 inserted in anaperture 60 of frame 22 as can be seen in FIGS. 1 and 2. Drive pin 56 isformed of a suitable hardened material to withstand the repeated impactswith punch and die members 26 and 28 as the embossing mechanism isoperated.

A restraining spring 62 is seated in aperture 60 of frame 22 so that oneend bears upon the frame 22 while the other end bears upon a grip ring64, which is attached to drive pin 56. Alternatively, drive pin 56 canhave a projecting shoulder or head, rather than ring 64, to hold spring62. Spring 62 is a compression spring which biases the linkage elementsand solenoid shaft 42 into a rest position so that drive pin 56 isnormally spaced from the head of punch and die members 26 and 28,thereby permitting wheels 12 and 14 to be rotated without interferenceto position selected punch and die sets for embossing. The restrainingforce of spring 62 is preferably kept at as low a level as possible tofacilitate the adjusting of the solenoid current to minimize impactnoise as described in more detail below.

When the selected pair of punch and die elements 26 and 28 arepositioned in the embossing area, solenoid 40 is actuated to drive shaft42 toward the embossing area, thereby moving inner sleeve 44, outersleeve 50 and drive pin 56 toward the embossing area, striking punch ordie member 26 or 28 and forcing it into engagement with card 32 inembossing area 30. If sufficient travel of shaft 42 occurs and asufficient force is developed, the card will be embossed with thecharacter defined by the punch and die members 26 and 28.

An important advantage of the direct solenoid driven embossingmechanisms of this invention is that there need be no long delay betweenthe time that the selected embossing area of the card is in position andthe application of the punch and die to the card. In the prior artsystems using continuously rotating bail arms, there is an inherentdelay between the positioning of the card and the time when the bailarms are in the proper position to apply the embossing force. In suchsystems, each character is delayed by about one-half cam rotation foreach character. In the present system, solenoid 40 can be energized assoon as the card is in position to receive the character, and a shortertime is required to emboss a series of characters.

Because solenoid 40, if actuated with a single electrical drive pulse,provides a very sharp impact between driver pin 56 and punch or dieelement 26 or 28, in addition to the noise as the solenoid reaches itsinternal stop, an extremely noisy embossing operation occurs, unlessmodifications are made to the solenoid drive. This is due in part to thefact that the solenoid armature and linkage have a considerable masswhich is moving at a relatively high speed at the time that it overcomesthe compression force of spring 62 and impacts the surface of card 32.

In order to prevent noisy operation, it has been determined that thesolenoid 40 should be energized in two stages. In the first stage ofenergization, sufficient voltage is applied to the solenoid forsufficient time merely to allow drive pin 56 to engage punch or diemember 26 or 28 and bring it into contact with the surface of card 32.After punch 26 and die 28 have been brought into contact with card 32,solenoid 40 is energized again for a longer time interval to apply forceto the punch and die member to emboss the card. Because punch and die 26and 28 are already in contact with card 32 when the embossing force isapplied, the loud impact noise of the printing elements striking thecard is avoided and the pressure applying step necessary for completionof the embossing operation occurs with little noise. The impact of themovable solenoid shaft 42 against the internal stop is also reducedbecause the control of the energization pulse reduces the velocity ofthe moving parts without reducing the embossing force. Using anextremely short interval for the first voltage application to solenoid40 results in a much lower impact force between the face of the typeelement and card 32 and therefore reduces the total noise of theoperation without degrading the quality of the embossing. It also mayallow for longer life of the mechanical embossing elements.

Application of the embossing command voltage in two parts to accomplishquiet embossing can be performed by the control circuitry of theembossing machine. After the proper punch and die pair are in the embossarea 30 and card 32 is correctly positioned, the emboss command voltagemay be applied to solenoid 40. It has been found that optimum operationfor typical plastic card stock occurs when the initial voltageapplication lasts for approximately 4 msecs. followed by a period whenno voltage is applied for approximately 5 msecs. and then the voltage isapplied for a further 75 to 100 msecs. to complete the embossingoperation. Approximately 200 msec. is required to return the elements totheir rest position at the completion of the embossing operation.

A suitable circuit for driving solenoid 40 in response to a two partcommand signal is shown in FIG. 4. In that Figure, a full-wave rectifiercomprised of diodes D1 through D4 rectifies the AC voltage applied toinput terminals 80. The full wave rectified DC voltage is filtered byresistor R1 and capacitors C1 and C2. The voltage is then furtherfiltered by resistor R2 and capacitor C3 and limited to zener diode D6and applied to the collector of a photocoupled transistor 82 which inturn controls the flow of current to resistor R3 which develops thevoltage for controlling field effect transistor Q1 which provides thepower switching action for the winding of solenoid 40. A flyback diodeD5 suppresses the inductive voltage transient when switch Q1 is turnedoff with a strong current flowing in solenoid winding 40.

The circuit in FIG. 4 operates by turning the NPN transistor ofphotocoupled transistor 82 ON when light is received from photodiode 84in the photoconductor package in response to actuation of LED 84 by thepresence of a command voltage on terminals 86. The input to inputterminals 86 which can be provided by an output port of the computerused to control the operations of embossing mechanism 10 or by any othersuitable analog or digital circuitry which can provide the desired shortinitial pulse to allow the type elements to move into contact with thecard surface with minimum impact force and then to apply the fullembossing force after the type elements are in contact with the surfaceof the card, thereby minimizing the noise created by a full force impactof the type elements into the surface of a card.

The matching of the command signal for the solenoid can also be used tovary the embossing force and to form smaller characters in a shortinterval, while larger characters receive more force and a longer cycletime. With the solenoid of the preferred embodiment, nearly 50 msec. isrequired to allow the magnetic field to fully build up. Since theembossing force is directly proportional to the field strength, the full50 msec. is required to emboss characters like a capital "8" whichrequires about 250 pounds of embossing force. A simple "." requiresbetween 50 and 100 pounds of embossing force. That force can be built upin about 20 msec. The embossing forces can be matched to the characterbeing embossed by varying the time duration of the excitation tosolenoid 40 or by monitoring the current wave shape to solenoid todetermine when plunger 42 has stopped moving. The command applied toterminals 86 can have a different length for each character inaccordance with stored information in the electronic circuitry (notshown) used to select the characters and to otherwise control theoperation of the machine.

Between embossing operations, it is of course necessary to move drivepin 56 away from the type elements and to make certain that the typeelements have been retracted from the face of card 32. The type elementsmay each be provided with return springs as shown in FIG. 8C of U.S.Pat. No. 4,271,012, to assist them in returning to their rest positionas shown in FIG. 1, separated from the surface of card 32. In FIG. 1,return springs 29 can be mounted in each type element to provide aspring for returning the type element to the rest position.

In order to provide a more positive return force, a retractor plate 90is attached to a retractor arm 92 using an attachment screw 94.Retractor arm 92 is in turn secured to outer sleeve 50 using a screw 96and washer 98. Retractor hooks the flange 31 of the punch 26 or die 28and positively retracts that element from the embossing position assolenoid 40 is deenergized. The engagement of the retractor and dieelement 28 is shown in FIG. 5. An oversized slot 99 in retractor arm 92permits adjusting the extension of retractor plate 90. Use of retractorplate 90 may obviate the need for the individual return springs 29. Areverse current could also be applied to solenoid 40 to allow for aquicker return of plunger 42 thereby yielding faster cycle time.

For each of the embodiments shown, it will be seen that it is notnecessary for adequate embossing to utilize two solenoids 40 as shown inFIG. 1. It has been found that adequate operation at slower speedsoccurs if one of the two solenoids 40 is replaced by a cam 100, as shownin FIG. 6, the protruding surface of which forces one of the twocooperating embossing elements 26 or 28 toward embossing area 30 andcard 32 while the other element is driven by solenoid 40 in the mannershown in FIG. 1. Cam surface 100 which replaces one of the solenoids 40shown in FIG. 1 forces each of the type elements 26 or 28 toward card 32as shaft 16 is rotated to move the type elements on the type wheel pastthe cam surface.

FIG. 7 shows another embodiment of the embossing mechanism utilizing amodified coupling arrangement for linear solenoids aligned with the axisof movement of the punch and die elements 26 and 28, respectively. InFIG. 7, linear solenoids 40 are long stroke linear solenoids which moveshaft 42 a significantly greater distance upon actuation than solenoids40 shown in FIGS. 1 through 6. In FIG. 7, solenoid plungers 42 areaccelerated along the axis of movement of punch and die print elements26 and 28 when solenoids 40 are actuated. Plungers 42 then strike drivepins 56 which, in turn, are driven against the print elements 26 and 28to move them into embossing or imprinting contact with card 32. Asdistinguished from the embodiment shown in FIGS. 1 through 6, theembosser shown in FIG. 7 applies the embossing force during a relativelyshort time interval with a large embossing force The embossing energy isprovided by the kinetic energy of plungers 42 and drive pins 56 as theymove against punch and die members 26 and 28. Plungers 42 areaccelerated to a relatively high velocity by solenoids 40. Since theamount of energy imparted to print elements 26 and 28 is dependent uponthe square of the velocity of the impacting parts, the print elements 26and 28 are capable of providing a significant embossing force which maybe suitable for embossing metal, cards which require more embossingforce such as cards 32, for example. Plastic cards can, of course, alsobe embossed.

After the embossing force is applied to punch and die members 26 and 28,a restoring force is provided by spring 62 which bears upon frame 22 atone end and a retaining clip 102 mounted at the end of drive pin 56which was struck by plunger 42 to effect the embossing operation. As wasthe case with the embodiments shown in FIGS. 1 through 6, the embodimentshown in FIG. 7 provides a relatively simple linkage since the solenoidsused to generate the embossing force provide their linear output forcealong the axis of movement of embossing elements 26 and 28.

FIG. 8 shows another form of embossing mechanism utilizing rotarysolenoids 104, rather than linear solenoids 40, to generate theembossing forces. Solenoid 104 has an output shaft 106 which is rotatedupon actuation of the solenoid. Shaft 106 drives a link 108 which ispivotally connected to a further link 110 which is, in turn, pivotallyconnected to drive pin 56 which is supported in an oil-lite bearing 59which defines an aperture through frame 22 for supporting shaft 56 forlinear oscillatory motion along the printing axis of punch and die printelements 26 and 28. As shown in FIG. 8, rotation of shaft 106 of rotarysolenoids 104 moves the linkage formed of links 108 and 110 from thesolid line positions shown in FIG. 8 to the positions shown in phantomoutline. As shaft 106 rotates to move the linkage, it can be seen thatdrive pins 56 are forced into contact with punch and die members 26 and28, thereby applying a suitable embossing force to those members to forma character on card 32. As distinguished from the structure shown inFIG. 7, the structure shown in FIG. 8 operates relatively quietlybecause there is no impact between a rapidly moving relatively massiveelement, such as shaft 42, and drive pin 56. Because the distancebetween drive pin 56 and punch and die members 26 and 28 is relativelysmall, there is little acceleration of drive pin 56 before it engagesprint elements 26 and 28 so the impact noise is held to a minimum.Depending somewhat upon the speed of actuation of solenoids 104, thestructure shown in FIG. 8 may apply a somewhat lesser embossing forceover a longer time duration than does the impact embosser structureshown in FIG. 7.

In order to drive the structure shown in FIG. 8 from the position shownin dotted outline to the position shown in solid line, it is necessaryto have a force applied by rotary solenoids 104 in a direction oppositeto that it was applied at the time that they were actuated to initiatethe embossing operation. Such a force can be provided by a spring biasarrangement which would return the linkage to the initial position.Although it is less desirable, the embossing operation can beaccomplished with a solenoid which is selectively energized betweenembossing steps and uses spring force to effect the embossing when theenergization is removed. The mechanism can alternatively be provided bya double-acting solenoid which, when actuated in the reverse direction,drives from the position shown in dashed outline to the initial positionto effectuate a second embossing operation.

In FIG. 9, a further embodiment of the solenoid driven embossingmechanism is shown. As was the case with the other forms of theembossing mechanism, the punch and die elements 26 and 28 are mounted inthe same manner relative to card 32. A single linear solenoid 40 drivesa shaft 42 which is connected to a pair of links 120 and 122 which arein turn pivotally connected at one end to links 120 and 122 and haveadjusting screws 130 and 132 inserted in suitable threaded openings attheir other ends. Links 124 and 126 are pivotally supported at alocation between the ends by suitable clevis and bearing arrangements134 and 136, respectively. When shaft 42 of solenoid 40 is actuated toretract shaft 42 into the body of solenoid 40, links 120 and 122 movefrom the position shown in solid lines in FIG. 9 to the position shownin dashed lines, forcing the bottom ends of links 124 and 126 away fromthe axis of shaft 42 and forcing adjusting screws 130 and 132 intopressure applying contact with punch and die elements 26 and 28 toemboss the surface of card 32. As was the case with the structure shownin FIG. 8, solenoid 40 can either be a double-acting solenoid to applyan embossing force each time shaft 42 moves between the two positionsillustrated or, alternatively, solenoid 40 can be single-acting with abiased restoring spring to return shaft 42 to the initial position afteran embossing cycle when the printwheels 12 and 14 are positioned so thatno punch and die members 26 and 28 are engaged by adjusting screws 130and 132 during the portion of the cycle when the solenoid returns to itsinitial position.

FIG. 10 also illustrates an embossing mechanism where a single solenoidis used to provide the embossing force for both the punch and diemembers. As distinguished, however, from the embodiment shown in FIG. 9,the embodiment shown in FIG. 10 utilizes a rotary solenoid 104 whichdrives a shaft 106 which is in turn, connected to a link 108 which ispivotally connected to one end of a connecting link 110', the other endof which is pivotally connected to a sliding shaft 112 which isrestrained for movement along an axis perpendicular to that of shaft 16.The link 108 and the link 110' cooperating to form a crank arm. Furtherlinks 140 and 142 are pivotally connected to sliding shaft 112 which isrestrained from movement other than along the axis of track 114. Asshaft 106 and link 108 are rotated from the position shown in solid linein FIG. 10 to the position shown in dashed line, sliding shaft 112 andlinks 140 and 142 attached thereto are moved from the solid lineposition to the dashed line position illustrated and further links 124and 126 pivot such that adjusting screws 130 and 132 engage printelements 26 and 28 and emboss a character on card 32. As was the casewith the rotary embosser embodiment shown in FIGS. 8 and 9, theembodiment in FIG. 10 can be operated either in a double-acting modeutilizing separate coils to drive the rotary solenoid to and from eachof the two operating positions or, alternatively, the solenoid can besingle-acting with a return spring returning the mechanism to an initialposition after a character is embossed and the printwheel is rotated tomove print elements 26 and 28 out of line with the adjusting screws 130and 132 at the ends of links 124 and 126.

FIG. 11 is an additional embodiment of the embossing mechanism utilizinga pair of rotary solenoids 104 which couple their rotary action to driveforces applied to type elements 26 and 28 utilizing links 124 and 126.Each of the rotary solenoids 104 drives shaft 106 which is rigidlyconnected to one end of link 108, the other end of which is pivotallyconnected to one end of link 110", the other end of which is pivotallyconnected to the end of link 124 or 126 which is opposite to the end towhich adjusting screw 130 or 132 is attached. As was the case with theother rotary solenoid embodiments, solenoid 104 can either be single ordouble acting.

FIG. 12 shows a simplified rotary solenoid linkage where rotarysolenoids 104 drive shafts 106 which are directly connected to one endof link 108, the other end of which carries adjusting screws 130 and132. Solenoids 104 are actuated to rotate shaft 106 and link 108 toapply direct embossing force to punch and die elements 26 and 28 toadjusting screws 130 and 132. These solenoids can either bedouble-acting to return them to the initial position or can be biased toreturn to their initial position using spring force after the actuatingenergy is removed.

For each of the embossing embodiments shown, it can also be seen that itis not necessary to have punch and die elements installed in wheels 12and 14 in all applications. In some applications, it will be found thata punch and anvil set is the desired combination to carry out embossingoperations with a carbon release paper positioned between the punch typeelements and the card to print a character into the surface of the cardwhile the reverse side of the card is supported by the movable anvilelement having a flat surface. The solenoid embossing mechanismaccording to the present invention provides superior results in thatapplication as well as the other applications illustrated.

It will be seen that the preferred and alternative embodiments of thepresent invention as described herein are not the only forms in whichthe present invention provides superior results. Other linkagearrangements can be utilized without departing from the scope of theinvention which is limited only by the following claims:

What is claimed is:
 1. In apparatus for embossing sheet material withcharacters including a plurality of cooperating print elements insertedin slots positioned about the circumference of cooperating print wheelsrotatable in coordination with each other on a frame to permitpositioning of a pair of print elements with one element on each side ofsheet material positioned in an embossing area; an improved embossingforce applying mechanism comprising, in combination:(a) a solenoidmounted on the frame, the solenoid having a shaft and being constructedand arranged when energized for effecting movement of the shaft from afirst position to a second position whose position is sensed bymonitoring the current; (b) linkage means coupled to the shaft of thesolenoid constructed and arranged for imparting motion, along theembossing axis, to a print element of a pair of print elements, theprint elements being disposed in axial alignment in the embossing area;and (c) solenoid driver means for selectively applying energy to thesolenoid to move the shaft between the first and second positions,during which the sheet material is embossed with a permanently deformedselected character, the driver means including means for energizing thesolenoid in two stages, the first of which energizes the solenoid tobring the linkage means into contact with the print element and movesthe print element into close proximity with the sheet material which isthe first position and the second of which energizes the solenoid toapply embossing force to the print element continuously during movementof the print element from the first position to the second positionthereby permanently deforming the sheet material and reducing the noiseof the imprinting operation, the force applied by the solenoid to theprint element in the second stage being greater than the force appliedby the solenoid to the print element in the first stage, the printelement moving slower in the second stage than the first stage, thesecond stage lasting longer than the first stage, the driver meansaccessing prestored character information to determine the amount ofembossing force to be applied during the second stage when embossing aselected character whereby all characters are embossed a substantiallyuniform amount.
 2. The invention of claim 1 wherein the solenoidincludes at least one winding and one restraining spring means and thesolenoid driver means includes means for actuating the winding to movethe shaft in one direction from one of the first and second positions tothe other of the first and second positions and the restraining springmeans is coupled for returning the shaft to the original of the firstand second positions.
 3. The invention of claim 1 wherein the linkagemeans also includes mechanical means for engaging the type element forretracting it into the printwheel at the conclusion of a characterembossing step when the solenoid returns to the first position andceases to apply embossing force and a restraining spring returns thelinkage means and the solenoid shaft to the starting position.
 4. Theinvention of claim 1 wherein both of the print elements are driven bythe solenoid.
 5. The invention of claim 1 where one of the cooperatingprint elements is driven by the solenoid and the other is moved by theaction of cam means positioned adjacent the embossing area and adaptedfor moving only those print elements in the vicinity of the embossingarea from the printwheels for engagement with the solenoid driven printelement.
 6. The invention of claim 1 wherein the linkage means alsoincludes retractor means adapted for movement with the shaft forengaging the print element after an embossing operation to return theprint element to the printwheels.
 7. The invention of claim 1 whereinthe linkage means includes slidably supported drive pin means alignedwith the embossing axis and having one end thereof adjacent the printelement, the linkage means constructed and arranged for couplingmovement of the shaft of the solenoid to the print element.
 8. Theinvention of claim 7 wherein the linkage means is constructed andarranged for allowing the shaft of the solenoid to initially moveindependently of the drive pin means and for impacting the drive pinmeans to transfer kinetic energy from the shaft of the solenoid to thedrive pin means.
 9. The invention of claim 1 wherein the solenoid is alinear solenoid mounted beneath the printwheels having its shaft movablebetween the first and second positions along an axis perpendicular toand intersecting the rotational axes of the printwheels and wherein thelinkage means includes a beam pivotally mounted on the frame, a firstend of the beam constructed and arranged for engaging one of theprinting elements, the other end of the beam being coupled to the shaftof the solenoid means by a link constructed and arranged for causing thefirst end of the beam to apply embossing force to the printing elementwhen the shaft moves between the first and second positions.
 10. Theinvention of claim 9 wherein the linkage means includes beams forcoupling movement of the solenoid shaft to the printing elements of bothprintwheels.
 11. The invention of claim 1 wherein the solenoid is arotary solenoid mounted beneath the printwheels and having a crank armcoupled at one end to the shaft and pivotally coupled at the other endto a slidable member constrained from movement along an axisperpendicular to the shaft and wherein the linkage means includes a beampivotally mounted on the frame, a first end of the beam constructed andarranged for engaging one of the printing elements, the other end of thebeam being coupled to the slidable member by a link constructed andarranged for causing the first end of the beam to apply embossing forceto the print element when the shaft of the rotary solenoid moves from afirst to a second rotational position.
 12. The invention of claim 1wherein the solenoid includes at least one rotary solenoid mountedbeneath the printwheels, the shaft is movable between first and secondrotational positions, the linkage means includes a beam pivotallymounted on the frame, a first end of the beam being constructed andarranged for engaging one of the print elements, the other end of thebeam being coupled to the shaft of the rotary solenoid by a linkconstructed and arranged for causing the first end of the beam to applyembossing force to the print element when the shaft moves between thefirst and second rotational positions.
 13. The invention of claim 1wherein the solenoid comprises at least one rotary solenoid mounted onthe frame adjacent the printwheels, the linkage means having a crank armcoupled at one end to the shaft positioned such that the other endengages the print elements to apply an embossing force thereto when therotary solenoid is moved from a first rotational position to a secondrotational position.
 14. The invention of claim 1, wherein the solenoidincludes a linear solenoid for effecting linear movement of its shaftfrom a first to a second position.
 15. The invention of claim 1, whereinthe solenoid includes a rotary solenoid for effecting rotary movement toits shaft from a first to a second position.
 16. The invention of claim1, having only a single solenoid.
 17. The invention of claim 1, whereinthe shaft of the solenoid is aligned with an axis of linear movement ofthe pair of print elements.
 18. In apparatus for embossing sheetmaterial with characters including a plurality of cooperating printelements inserted in a slots positioned about the circumference ofcooperating print wheels rotatable in coordination with each other on aframe to permit positioning of a pair of print elements with one elementon each side of sheet material positioned in an embossing area; animproved embossing force applying mechanism comprising, incombination:(a) solenoid mounted on the frame, the solenoid having ashaft and being constructed and arranged when energized for effectingmovement of the shaft from a first position to a second position whoseposition is sensed by monitoring the current; (b) linkage means coupledto the shaft of the solenoid constructed and arranged for impartingmotion, along the embossing axis, to an element of a pair of printelements, the print elements being disposed in axial alignment in theembossing area; (c) solenoid drive means for selectively applying energyto the solenoid to move the shaft between the first and secondpositions, during which the sheet material is embossed with apermanently deformed selected character, the driver means includingmeans for applying voltage to the solenoid in two stages, the first ofwhich energizes the solenoid to bring the linkage means into contactwith the print element and move the print element into close proximitywith the sheet material which is the first position and the second ofwhich energizes the solenoid to apply embossing force to the printelement continuously during movement of the print element from the firstposition to the second position thereby permanently deforming the sheetmaterial and reducing the noise of the embossing operation; and (d)wherein the solenoid includes a rotary solenoid mounted beneath theprintwheels and having a crank arm coupled at one end of the shaft andpivotally coupled at the other end to a slidable member constrained frommovement along an axis perpendicular to the shaft wherein the linkagemeans includes a beam pivotally mounted on the frame, a first end of thebeam constructed and arranged for engaging one of the print elements theother end of the beam being coupled to the slidable member by a linkconstructed and arranged for causing the first end of the beam to applyembossing pressure to the print element when the shaft of the rotarysolenoid moves from a first to a second rotational position, the drivemeans accessing prestored character information to determine the amountof embossing force to be applied during the second stage when embossinga selected characters whereby all characters are embossed asubstantially uniform amount.
 19. The invention of claim 1 wherein thevelocity of the shaft of the solenoid slows down substantially betweenthe first and second stages.
 20. In apparatus for embossing sheetmaterial with characters including a plurality of cooperating printelements inserted in slots positioned about the circumference ofcooperating print wheels rotatable in coordination with each other on aframe to permit positioning of a pair of print elements with one elementon each side of sheet material positioned in an embossing area; animproved embossing pressure applying mechanism comprising, incombination:(a) a solenoid mounted on the frame, the solenoid having ashaft and being constructed and arranged when energized to effectuatemovement of the shaft from a first position to a second position whoseposition is sensed by monitoring the current; (b) linkage means coupledto the shaft of the solenoid constructed and arranged for impartingmotion, along the embossing axis, to an element of a pair of printelements, the print elements being disposed in axial alignment in theembossing area; and (c) solenoid drive means for selectively applyingenergy to the solenoid to move the shaft of the solenoid between thefirst and second positions, during which the sheet material is embossedwith a permanently deformed selected character, the solenoid drivermeans including means for energizing the solenoid in two stages, thefirst of which energizes the solenoid to bring the linkage means intocontact with the print element and moves the print element into closeproximity with the sheet material which is the first position and thesecond stage of which energizes the solenoid to apply embossing force tothe print element continuously during movement of the print element fromthe first position to the second position thereby permanently deformingthe sheet material, the force applied by the solenoid to the printelement in the second stage being greater than the force applied by thesolenoid to the print element in the first stage, the print elementmoving slower in the second stage than the first stage, the second stagelasting longer than the first stage, the driver means accessingprestored character information to determine the amount of embossingforce to be applied during the second stage when embossing a selectedcharacter whereby all characters are embossed a substantially uniformamount.
 21. The invention of claim 1, wherein the first and secondstages are separated by a predetermined time interval.
 22. An apparatusfor embossing sheet material with characters including a plurality ofprint elements, comprising:(a) a solenoid having a shaft and beingconstructed and arranged when energized for effecting movement of theshaft from a first position to a second position whose position issensed by monitoring the current; (b) linkage means coupled to the shaftof the solenoid for imparting motion to a print element as the shaftmoves from the first to the second positions; and (c) solenoid drivermeans for selectively applying energy to the solenoid to move the shaftbetween the first and second positions, during which the sheet materialis embossed with a permanently deformed selected character, the solenoiddrive means including means for energizing the solenoid in two stages, afirst stage of which causes movement of the print element into closeproximity with the sheet material which is the first position, and asecond stage of which applies an embossing force to the print elementcontinuously during movement of the print element from the firstposition to the second position, the printer element moving slower inthe second stage than the first stage, the second stage lasting longerthan the first stage, the driver means accessing prestored characterinformation to determine the amount of embossing force to be appliedduring the second stage when embossing a selected character whereby allcharacters are embossed a substantially uniform amount.
 23. A method forembossing sheet material by use of print elements and at lest onesolenoid, the method comprising the steps of:(a) positioning a selectedprint element in alignment with a surface area of the sheet material tobe embossed with the selected print element; and (b) energizing thesolenoid, including first energizing the solenoid to cause movement ofthe selected print element into close proximity with the sheet materialto be embossed which is a first position and secondly energizing thesolenoid to apply an embossing force to the selected print elementcontinuously during movement of the print element to a second positionwhose position is sensed by monitoring the current, the print elementbeing moved slower and longer during the second energization wherebyembossing of the sheet material is accomplished by prestored characterinformation being accessed to determine the amount of embossing force tobe applied when embossing a selected character whereby all charactersare embossed a substantially uniform amount.